The application relates to a photographic system, including photographic products and processes, which utilize compounds capable of releasing a quaternary upon contact with an aqueous alkaline processing composition. The application also relates to novel compounds.
In various photographic systems for forming images, whether in black and white or in color, it is often desirable to include in the photographic film unit one or more of the various photographic reagents required for development and/or to enhance image quality. This practice extends to both conventional systems for forming negative images and also to various systems such as diffusion transfer wherein a positive image in silver or in color is obtained. In many instances the photographic reagent may be contained initially in either the processing composition applied for development and image formation or in the film unit itself. The latter embodiment is typically preferred so as to reduce the number of ingredients required in the processing composition. In other instances the particular photographic reagent desired is not sufficiently stable in alkali to provide the requisite shelf life for the processing composition or the reagent is not compatible and/or reacts with another reagent in the processing composition and therefore must be contained initially in the film unit. In still other instances the reagents must be provided at some particular time in the development process which requires that it be present in a specified layer or in specified proximity to another layer in the film unit.
In all the foregoing instances it is desirable that the reagent be contained in the desired layer or layers of the film unit in a form that is stable and non-migratory or non-diffusible and yet available when it is required at a particular time in the development process. To accomplish this result it is known in the art to attach to the particular photographic reagent a blocking moiety which prevents the reagent from reacting with other photographic materials present in the film unit or migrating or diffusing prior to the time when photographic development is effected but which will release the photographic reagent at the desired time such as by reaction with the aqueous alkaline processing composition.
The present application relates to a photographic system wherein development of an exposed photosensitive element is carried out in the presence of a compound which provides a controlled release of a quaternary during the development process and to novel compounds.